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Subject: Re: Will next version of Junior have underpromotion code?

Author: Dave Gomboc

Date: 21:56:53 06/07/99

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On June 07, 1999 at 20:29:58, Dann Corbit wrote:

>On June 07, 1999 at 20:20:25, Dave Gomboc wrote:
>[snip]
>>At least for the present, it is only an opinion.
>>
>>Minimax has a way of removing the horrible error in end-point evaluations.  It's
>>pretty rare that missing an underpromotion will actually hurt you.
>In the sample I examined, about 7% of the time it scores lower than always
>queening.  I can send a list of such EPD's to anyone who would like a copy.

Your sample includes only games in which promotion actually occurs, and the 7%
includes many positions where promoting to a rook might be slightly better, but
if the person playing had overlooked the possibility to underpromote, they could
have still won the game my promoting to a queen, either with the same move
sequence, or a different one.  The important figure would represent how often
the rough evaluation of a position (e.g. clearly winning) depends upon a
promotion, and how many of these cases there are in which a queen will never
work.

When you look for this, now you are counting practically every winning ending --
and many winning middlegames -- with pawns on the board that gets resigned.  I
do not have a statistic to back up my thoughts on this matter, but I am
extremely confident that the rate of "necessary underpromotions" will be far
less than 7%.  0.0007% would be more like it.

Dave



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